Mad Men returns for a sixth season with a two-hour premiere Apr. 7 on AMC. What better way to celebrate than with a groovy Sterling Cooper Draper cocktail party featuring the full cast? Check out the newly released color season 6 promo photos — plus previously released black-and-white shots — of the boozy ’60s shindig, which includes handsome star Jon Hamm and gay faves Elisabeth Moss and Christina Hendricks.